注射型壳聚糖温敏相变复合材料的制备及性能研究

制备了一种注射型壳聚糖(CS)温敏相变复合材料,首先采用乳化-化学交联法,以戊二醛为交联剂,制备包载甲氨蝶呤(MTX)的壳聚糖微球,然后采用离子交联法,向CS溶液中滴加50%甘油磷酸钠溶液,制备CS温敏水凝胶。将CS载药微球分散于水凝胶中,制得温敏相变复合材料。结果表明,所制得的微球载药量为12.98%,包封率为32.66%,且粒径均一,分散性良好,具有良好的通针性;水凝胶在37℃下1min内可发生相变,由溶胶转变为凝胶,具有良好的温度敏感性;制备的温敏相变复合材料具有良好的原位注射性,且4h内药物释放率为35.65%,缓释效果明显。     

空心磁性微球负载La掺杂TiO_2的制备和光催化性能

以自制的粒径均一的分散P(St-AA)聚合物微球为模板,制备了P(St-AA)/Fe_2O_3纳米颗粒,热处理后获得纳米磁性空心微球;在用溶胶-凝胶法制备La掺杂TiO_2基础上,制备了以磁性空心微球为载体的空心磁性微球负载La掺杂TiO_2。紫外光催化实验结果表明,该产品降解亚甲基蓝的效率优于同等条件制备的La掺杂TiO_2。     

以碳酸钙为模板制备空心羟基磷灰石微球及其表征

以碳酸钙为模板和钙源,与磷酸氢二铵通过水热反应,制备出尺寸均匀、形态规则的空心羟基磷灰石微球。采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)、透射电镜(TEM)测试制备的样品,结果显示,制备的空心羟基磷灰石微球具有与碳酸钙微球模板相似的形貌,空心,尺寸均匀且形貌规则。并通过改变水热反应时间探索了羟基磷灰石微球的形成机理。此羟基磷灰石空心微球在生物医学领域具有较大的应用前景。     

正辛胺模板法制备Si／Al复合空心微球及其结构表征

以正辛胺为模板、正硅酸乙酯(TEOS)为硅源、异丙醇铝为铝源,在盐酸的催化作用下通过溶胶一凝胶方法制备出圆形度和分散性好、结构完整的Si/Al复合空心微球.分析了不同反应时间和反应温度下Si/Al复合空心微球的形貌、粒径、成分和结构.结果表明:Si/Al复合空心微球的平均粒径随反应温度和反应时间的增加而缓慢增大,但明显小于同样条件SiO2空心微球的粒径.Si/Al复合空心微球的平均粒径为8～16μm,壳层厚度为2.18～3.61μm.Si/Al复合空心微球中的铝主要以氧化物的形式存在;壳层表面具有微孔结构,比表面积为431～912 m2/g;可几孔径为1.2～2.0nm.     

铕掺杂的TiO2空心微球的制备及光催化性能

通过溶胶-凝胶法制备未掺杂和铕掺杂的TiO₂空心微球, 采用XRD、SEM、TEM、HRTEM、BET和XPS等技术对样品进行表征, 以亚甲基蓝的光催化降解为目标反应, 评价其光催化活性。结果表明, 钛酸四丁酯(TBOT)的加入量对微球的形貌影响较大, 当滴加1.5 mL的TBOT时, 可得结构清晰、分散性良好的TiO₂空心微球。XRD分析表明, 400℃煅烧的纳米TiO₂空心微球为锐钛矿, 掺铕可抑制TiO₂的晶相转变。光催化实验表明, 铕掺杂能显著提高TiO₂空心微球的活性。当铕掺量为0.7%时, 所得样品粒径和孔径最小, 比表面积最大, 光催化活性最高。     

纳米羟基磷灰石/壳聚糖复合微球的原位仿生制备及表征

为解决纳米羟基磷灰石/壳聚糖(nHA/CS)复合微球中nHA团聚及分散不均的问题, 本研究在油包水的乳液体系中, 原位仿生制备了nHA/CS复合微球, 并与共混法制备的nHA/CS复合微球进行了对比研究。利用扫描电镜(SEM)、X射线能谱(EDS)、X射线衍射(XRD)、红外(FTIR)和激光粒度仪等手段对不同微球的理化性能进行表征。结果表明: 相比共混法, 原位仿生制备的nHA/CS复合微球形态圆整均匀, 分散性好, 粒径分布较窄, 平均粒径为8.62 μm, nHA晶体均匀分布在微球内部及表面, 并与CS基质以化学键结合。该复合微球有望用于骨组织工程及药物控制释放。     

纳米缺钙羟基磷灰石/壳聚糖复合微球的原位均匀制备

针对纳米缺钙羟基磷灰石/壳聚糖(nCDHA/CS)复合微球中,nCDHA在微球中分布不均和含量不足的问题,在油包水(W/O)体系中,运用均匀沉淀法原位制备了nCDHA/CS复合微球。利用扫描电镜(SEM)、粒度分析仪、X射线衍射(XRD)、傅里叶红外光谱仪(FT-IR)、热重分析(TG)、X射线光电子能谱仪(XPS)等对复合微球的理化性能进行了表征。结果显示,所制得的nCDHA/CS复合微球中,nCDHA均匀分布于复合微球中,其含量高达43%;复合微球粒径分布较窄,球形度良好,分散性指数(PDI)为0.291,平均粒径18.6μm。仿生矿化结果显示,复合微球表面矿化是从nCDHA生成nHA的过程,仿生矿化14 d后,微球表面形成大量均匀的片状类骨磷灰石,表明该复合微球具有较好的生物学性能,对骨组织再生修复具有较大的潜力。     

利用双重乳液法制备蜂窝状聚砜空心微球

通过W/O/W型双重乳液法制备蜂窝状聚砜(PSF)空心微球。研究了油相表面活性剂的类型、油水比及准备温度的影响。结果表明,油相表面活性剂的类型是决定PSF微球形貌的主要因素;第二次乳化的油水比影响微球的形成;准备温度能有效地控制微球表面孔的多少。     

聚烯丙基氯化铵调控下多孔羟基磷灰石微球的合成及作为药物载体的应用研究

选用聚烯丙基氯化铵(PAH)作为晶体生长调节剂, 在水热条件下成功制备了多孔羟基磷灰石(Hydroxyapatite, HAP)中空微球。详细研究了反应时间和添加剂浓度等因素的影响: 150℃水热反应12 h, 控制PAH 浓度0.3~0.5 g/L, 可合成尺寸均匀、孔径密集的HAP中空微球。微球生长经历早期前驱体微结构、异相成核、相转化等不同阶段, 聚合物在各阶段都起到重要的调节作用。以典型的布洛芬(ibuprofen, IBU)作为模型药物, 研究微球的药物负载和脱附能力。结果显示: 多孔微球具有良好的药物负载和释放能力, 吸附量较好, 可达到413.65 mg/g。且药物具有较好的pH响应释放行为, 可作为pH敏感靶向药物载体应用到生物医学等领域。     

粒径及壁厚可控的二氧化硅空心微球的研究(英文)

二氧化硅空心微球是由模板/溶胶?凝胶法制备的,其中模板选用的是阳离子型聚苯乙烯(PS),前驱体采用的是正硅酸乙酯(TEOS).二氧化硅空心微球的空腔大小由PS模板的尺寸决定,所以通过改变聚合反应的参数(单体、引发剂、稳定剂、分散介质的极性),可以制得粒径范围在0.71～1.80μm的二氧化硅空心微球.改变TEOS的浓度为0.4～0.8mmol/L,可以得到壁厚为20～60nm的二氧化硅空心微球.空心微球的粒径和壁厚将会影响粉体的堆积密度,而这同样会影响到以二氧化硅空心微球为原料制备的材料的热导率及强度.     

Microstructured microspheres of hydroxyapatite bioceramic

Hydroxyapatite (HAP) particles having spherical geometry and 125–1000 m in size range were prepared using a solid-in-water-in-oil (S/W/O) emulsion, cross-linking technique. An aqueous solution of chitosan containing different loading of HAP was dispersed as droplet in liquid paraffin using a stabilizing agent. Cross-linking of chitosan was induced by adding appropriate amount of glutaraldehyde saturated toluene. Chitosan microspheres containing HAP were sintered at 1150 °C to obtain pure HAP microspheres. The spheres thus produced were examined by scanning electron microscopy. The percentage yield and size distributions of the spheres were also determined.     

α-Ni(OH)2/SiO2核壳以及α-Ni(OH)2空心微球的制备及表征

采用以正硅酸乙酯(TEOS)水解为基础的硅溶胶种子生长法制备了粒径约为270nm的近单分散二氧化硅球型颗粒.采用一种新的溶液生长法,以氢氟酸作为溶液中镍离子配位剂,加入氨水调节溶液pH值的同时作为镍离子补充配位剂,60℃水浴条件下在已制得SiO2微球表面均匀包覆α-Ni(OH)₂得到Ni(OH)₂/SiO₂核壳结构,Ni(OH)₂壳层厚度约为35nm.结合多步包覆法提高Ni(OH)₂壳层厚度,三次包覆后壳层厚度达到约100nm,四次包覆后约为140nm.采用20wt％的强碱NaOH溶液对三次包覆后的Ni(OH)₂/SiO₂核壳结构进行处理,得到了壳层厚度约为95nm的α-Ni(OH)₂空心微球.空心微球具有较大的比表面积为141.06m²/g.     

Solvothermal synthesis of magnetite hollow submicrospheres and mesoporous nanoparticles

Magnetite hollow submicrospheres and mesoporous nanoparticles have been synthesized by a solvothermal approach with assistant of hexamethylenetetramine (HMT) and poly(vinyl pyrrolidone) (PVP). Experimental results showed that the morphology of magnetite was transformed from hollow to solid submicrospheres with increasing amount of HMT. Moreover, without addition of PVP or appropriate addition of external water, mesoporous nanoparticles were obtained. A probable gaseous bubble template mechanism was proposed for the formation of magnetite hollow and mesoporous nanostructures based on experimental observations. Magnetic measurement results revealed that all of the samples were ferromagnetic at room temperature.     

壳聚糖/聚(N-异丙基丙烯酰胺)全互穿网络水凝胶的制备及性能

以壳聚糖(CS)和N-异丙基丙烯酰胺(NIPAAm)为原料,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,制备具有温度和pH值双敏感性的全互穿网络水凝胶(Full-IPN);利用红外光谱(FT-IR)对其分子结构进行表征,扫描电镜(SEM)观察其内部形貌,并通过DSC对其低临界溶解温度(LCST)进行表征,最后研究了不...     

Hollow CoNi alloy submicrospheres consisting of CoNi nanoplatelets: Facile synthesis and magnetic properties

Magnetic alloy micro/nanostructures with controllable size and morphology have drawn intensive attention due to their interesting physicochemical properties and potential applications in micro/nanodevices. In this letter, CoNi hollow submicrospheres consisting of CoNi nanoplatelets with a thickness of ca. 10 nm have been successfully synthesized via a facile wet-chemical approach free of any template or surfactant. Scanning electron microscope (SEM) and transmission electron microscope (TEM) images indicate that the diameter and shell thickness of the as-prepared hollow submicrosphere are ca. 600 nm and 200 nm, respectively. Elemental maps demonstrate that Co and Ni elements are distributed homogeneously in the CoNi hollow submicrosphere. Magnetic measurement reveals that the hollow submicrospheres display ferromagnetic behaviour with a coercivity of 109.5 Oe.     

壳聚糖透明质酸复合水凝胶的制备及性能

用零长度的1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC·HCl)和N-羟基丁二酰亚胺(NHS)作为偶联剂和稳定剂制备了壳聚糖基透明质酸复合水凝胶,探讨了溶液pH值对该类水凝胶溶胀性的影响。溶液的pH在4.0时,该类水凝胶的溶胀率最低,升高和降低溶液的pH,该类水凝胶的溶胀率均升高,文中还对水凝胶的降解率进行了研究,实验发现,交联后的水凝胶具有一定的稳定性。包埋在此水凝胶中的牛血清蛋白(BSA)释放随载药介质pH值的变化而显著不同,pH 7.4条件下载药的水凝胶释药率大于pH 1.2条件下的释药率。因此,具有pH敏感性的壳聚糖透明质酸复合水凝胶在药物运输领域具有潜在的应用。     

纳米银/壳聚糖复合水凝胶的原位制备、表征及抗菌性能研究

在壳聚糖/1,2-丙二醇凝胶中采用抗坏血酸原位还原硝酸银生成纳米银,进而通过碱液置换得到具有不同纳米银含量的物理交联的纳米银/壳聚糖复合水凝胶.紫外-可见光谱、X射线衍射图谱和低分辨率TEM照片的结果表明,复合水凝胶内形成了分散良好的纳米银.高分辨率TEM照片结果表明纳米银的直径在20～50nm之间,但其结晶状态并不均一.抗菌性实验证明,纳米银/壳聚糖复合水凝胶对大肠杆菌和金黄色葡萄球菌均有抗菌效果.     

透明温敏性羧甲基壳聚糖配合物凝胶的制备

利用羧甲基壳聚糖(CM CS)与甘油磷酸盐(GP)互配,制备了在25℃~70℃具有响应功能的透明水凝胶体系。探讨了CM CS羧甲基取代度(D S)、GP的浓度和盐酸的浓度等因素对凝胶性能和透明度的影响。结果表明,D S介于0.3~0.6的CM CS与GP互配,可以得到温敏性透明状水凝胶,其透明度随着D S的增大而递增;随环境温度的升高和恒温时间的延长,其透明度降低;随着D S的增大,环境温度和恒温时间对配合物凝胶透明度的影响减弱。     

Development and in vitro characterization of chitosan-based microspheres for nasal delivery of promethazine

Conventional and composed promethazine-loaded microspheres were prepared by spray drying of chitosan solution systems and double water-in-oil-in-water (W/O/W) emulsion systems, respectively. Double emulsions were prepared in two different feed concentrations, with chitosan dissolved in both water phases, and ethylcellulose dissolved in oil phase. Swelling and bioadhesive properties of the microspheres depended on the chitosan content, type and the feed concentration of spray-dried system. Results obtained suggested that better ethylcellulose microcapsules with promethazine in the chitosan matrix were formed when less concentrated emulsion systems were spray-dried. Thus, in case of such a system, with ethylcellulose/chitosan weight ratio of 1:2, prolonged promethazine release was obtained.     

Development and In Vitro Characterization of Chitosan-based Microspheres for Nasal Delivery of Promethazine

ABSTRACT

Conventional and composed promethazine-loaded microspheres were prepared by spray drying of chitosan solution systems and double water-in-oil-in-water (W/O/W) emulsion systems, respectively. Double emulsions were prepared in two different feed concentrations, with chitosan dissolved in both water phases, and ethylcellulose dissolved in oil phase. Swelling and bioadhesive properties of the microspheres depended on the chitosan content, type and the feed concentration of spray-dried system. Results obtained suggested that better ethylcellulose microcapsules with promethazine in the chitosan matrix were formed when less concentrated emulsion systems were spray-dried. Thus, in case of such a system, with ethylcellulose/chitosan weight ratio of 1:2, prolonged promethazine release was obtained.